const title = Symbol('站点名称')
class WebSite {
  constructor(name) {
    this[title] = '喵喵大王'
    this.name = name
  }
  getName() {
    return `${this.name}，欢迎来到${this[title]}站点!`
  }
}

const Bob = new WebSite('Bob')
console.log(Bob.getName()) //=> Bob，欢迎来到喵喵大王站点!
for (const key in Bob) {
  console.log(key) //=> name
}
console.log(Object.keys(Bob)) //=> [ 'name' ]
